INCOMMENSURATE ANTIFERROMAGNETIC ORDERS AND PECULIAR ELECTRONIC-STRUCTURES IN THE DOPED HUBBARD-MODEL

In this letter we shall propose a new Hartree-Fock approach for the st andard two-dimensional Hubbard model. Commensurate antiferromagnetic o rder exists only for half-filling. Upon doping, incommensurate spiral antiferromagnetic orders appear and electronic states build into the h alf-filling energy gap. Corresponding Fermi surfaces enclose areas pro portional to the dopant concentrations so that the Hall concentrations scale with the dopant concentrations. These results are consistent wi th recent transport, neutron-scattering and photoemission experiments on the high-temperature cuprate superconductors.